Plated wire for underwater mooring applications



June 27, 1967 W. F. WARREN 3,328,140

PLATED WIRE FOR UNDERWATER MOORING APPLICATIONS Filed Jan. 9, 1964 FIG. I

FIG. 2 FIG. 3

William F Warren INVENTOR.

ATTORNEYS AGENT United States Patent 3,328,140 PLATED WIRE FOR UNDERWATER MOORING APPLICATIONS William F. Warren, Livermore, Califi, assignor to the United States of America as represented by the Secretary of the Navy Filed Jan. 9, 1964, Ser. No. 336,845 4 Claims. (Cl. 29191.6)

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

The present invention relates to a new and improved mooring line and more particularly to a mooring line which has metallic coatings thereon to provide protection against corrosion and also to provide protection against marine fouling.

Those concerned with development of an improved mooring line long recognized the need for a high tensile strength mooring line which retains its strength and is resistant to corrosion by the sea water and is also re sistant to fouling by barnacles, oysters and other marine fouling organisms. One approach to the problem has been to use a steel cable of extremely large diameter so that even after months and years of seawater corrosion there will still be sufficient diameter of cable to provide the minimum tensile strength required. Such cables are thick and relatively inflexible and difficult to handle. One attempt to prevent marine fouling on the cables has been to coat the cables with a grease-like film or coating, but this has proved to be unsatisfactory because such coatings readily rub off by abrasion and leave the cable exposed and unprotected.

The general purpose of this invention is to provide a mooring cable of high tensile strength but minimum diameter to reduce drag and to provide said cable with protection against corrosion by the seawater and further protection against marine fouling.

An object of the present invention is the provision of a method of protecting a mooring line against marine fouling.

Another object is to provide a method of protecting a mooring line from corrosion by the seawater.

Another object of the invention is to provide a method of protecting a mooring line against corrosion by the seawater and also against marine fouling.

A further object of the invention is the provision of a mooring line which is resistant to marine fouling.

Still another object is to provide a mooring line which is resistant to corrosion by the seawater.

Yet another object of the invention is to provide a mooring line which is resistant to both marine fouling and corrosion by the seawater.

A still further object of the invention is to provide a mooring line of high tensile strength but small diameter which is resistant to corrosion by the seawater and fouling by marine organisms.

Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings wherein:

FIG. 1 is a plan view, taken partially in section, of the mooring line and the swaged end fitting;

FIG. 2 shows a section of the device taken on line 2-2 of FIG. 1 looking in the direction of the arrows;

FIG. 3 is a plan view, taken partially in section, showing details of the end fitting; and

FIG. 4 illustrates a plan view of a modification of the device, taken partially in section.

Referring now to the drawing, there is shown in FIG.

l a mooring line 5 having an end fitting 10 thereon. The mooring line consists of a high tensile strength wire 6 having a first metallic coating 7 thereon and a second metallic coating 8 over the first coating. The high tensile strength wire 6 may consist of aircraft wire, music wire, ultra strength carbon steel wire, ultra strength stainless steel wire, piano wire, or wire made of beryllium copper, fiberglass, titanium, or Monel metal. The wires preferably have a tensile strength from 300,000 p.s.i. to 600,000 p.s.i. to provide a mooring line of sufiicient strength but minimal diameter so that the wire will have a low drag in the water. Wire 6 is provided with a first continuous metallic coating 7 of a metal which is of higher chemical nobility than wire 6 and is further provided with a final coating 8. The first coating 7 provides wire 6 with protection against corrosion by the seawater and further protection against galvanic corrosion by the outer coating 8. A hard impervious corrosion protection is provided when coating 7 consists of nickel which is of .001 to .003 inch in thickness. It has also been found that a hard irnperious corrosion protection may be provided by a first coating of other metals such as Monel, Inconel, silver, or titanium.

It has been found that certain metals, when in contact with seawater, will react with the seawater to produce metallic ions in the vicinity of the metal, which ions are toxic to marine fouling organisms. Taking advantage of this discovery, the mooring line is provided with a final coating 8, preferably of copper, to protect the mooring line against marine fouling. When in contact with salt water, the copper coating on the mooring line slowly corrodes to produce copper ions which are toxic to potential fouling organisms and hence maintains the mooring line free of such fouling. Other metals may be used for the final coating 8, such as bronze, brass, or any other copper alloy containing at least of copper.

The mooring line of this invention is provided with an end fitting 10, shown in detail in FIG. 3, which is a cupshaped member 11 which is placed upon the end of the mooring line and secured thereto by swaging. The end fitting is made of a metal, such as K Monel, having a chemical nobility higher than that of the wire 6 and the plating materials 7 and 8, and is provided with an outer coating 12 of the same material as the outer coating 8 on wire 6. The coated end fitting therefore resists marine fouling in the same manner as does the mooring line and also protects the ends of the mooring line from corrosion by seawater and from galvanic corrosion and cracking of the fitting.

In instances when the mooring line wire 6 is made of a metal which is of a higher chemical nobility than the copper or copper alloy which is used as the final coating, the first or intermediate coating 7 may be eliminated, such as is shown in the embodiment illustrated in FIG. 4.

From the preceding it may be seen that a new method is provided for protecting an underwater body against corrosion and further protecting said body against fouling by marine organisms. When the method is applied to mooring applications, a new and improved mooring line is provided, said mooring line having an initial corrosion protective coating thereon and an outer anti-fouling coating thereon.

Obviously many modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

Having thus described the invention, what is claimed is:

1. The method of preserving a flexible metallic body from seawater corrosion and also protecting said "body from marine fouling comprising forming directly upon said body a first continuous coating of a metal having a higher chemical nobility than said body,

then forming upon said body and over said first coating an outer continuous coating of a metal having the characteristic of reacting with seawater to produce metallic ions which are toxic to marine fouling organisms,

whereby the first coating protects said body from corrosion by the seawater and also from galvanic corrosion by the outer coating, while the outer coating protects the body from marine fouling.

2. The method of protecting a flexible metal mooring line from corrosion and marine fouling comprising the steps of forming a continuous coating of nickel directly upon said line and forming an outer continuous coating of copper upon the nickel plated line, whereby the copper coating slowly corrodes by action with seawater forming copper ions which are toxic to marine fouling organisms, and the nickel coating protects the line from corrosion by the seawater and also prevents galvanic corrosion by the copper.

3. A corrosion and fouling resistant flexible mooring line comprising a strand of material having a high tensile strength,

a first continuous metallic coating formed directly on said strand and being of a material of higher chemical nobility than said strand,

an outer continuous metallic coating formed on said first coating and being of a low chemical nobility metal having the characteristic of reacting with salt water to produce metallic ions which are toxic to marine fouling organisms.

4. The mooring line of claim 3 further comprising a cup-shaped end fitting swaged onto each end of said flexi'ble mooring line, the end fittings being of a metal of higher chemical nobility than both said wire and said coatings, said end fittings having an outer continuous coating formed thereon of the same material as said outer coating on said wire.

References Cited UNITED STATES PATENTS Re. 25,043 9/1961 Bul-ow 75-159 2,002,263 5/1935 Domn 29-1963 2,145,248 1/=1939 Chace 29-1963 3,219,505 11/1965 Hilding 10615 FOREIGN PATENTS 8,633 1908 Great Britain.

DAVID L. RECK, Primary Examiner.

HYLAND BIZOT, Examiner.

R. O. DEAN, Assistant Examiner. 

3. A CORROSION AND FOULING RESISTANT FLEXIBLE MOORING LINE COMPRISING A STRAND OF MATERIAL HAVING A HIGH TENSILE STRENGTH, A FIRST CONTINUOUS METALLIC COATING FORMED DIRECTLY ON SAID STRANDS AND BEING OF A MATERIAL OF HIGHER CHEMICAL NOBILITY THAN SAID STRAND, AN OUTER CONTINUOUS METALLIC COATING FORMED ON SAID FIRST COATING AND BEING OF A LOW CHEMCAL NOBILITY METAL HAVING THE CHARACTERISTIC OF REACTING WITH SALT WATER TO PRODUCE METALLIC IONS WHICH ARE TOXIC TO MARINE FOULING ORGANISMS. 